He was later appointed as military attaché at the Colombian Embassy in the United States and national representative to the Inter-American Defense Board, so the whole family moved to live in Washington, DC.

Pizarro was involved in the organization of the only student strike of the university, and soon joined the Juventud Comunista Colombiana (JUCO, Colombian Communist Youth).

Pizarro was among those who were contacted by the guerrilla, and following these early contacts an 18 year old Pizarro decided to move to the countryside without completing his degree to engage in social work in the zones marked by the political violence that had occurred during and after the La Violencia period, and which were under the control of communists who had been liberals during the time, including the regions of Puerto Boyacá and Yacopí.

During these days the guerrilla soldiers were essentially armed farmers and their economic support came for their growing crops to sell, with interspersed combats with the army.

Pizarro and the young and few members of the urban front started to have confrontations with the traditional leaders of FARC who mostly disregarded them, and resented their views.

Back in the city he reestablished his contact with his old friend Jaime Bateman, Álvaro Fayad "the Turk", Luis Otero Cifuentes, Vera Grabe, Iván Marino Ospina and others.

[5] After 19 years in operation, the group, commanded by Pizarro, began negotiating with the Colombian government, in April 1989, for demobilization conditional on certain grounds.

[7] The accord was signed in the town of Santo Domingo by Jaime Pardo Rueda, adviser to the president, Raul Orejuela Bueno, Minister of Interior and Pizarro, Commander of M-19.

He was assassinated shortly thereafter aboard an Avianca Airlines Boeing 727 plane flying from Bogotá to Barranquilla on April 26, 1990, by a young paramilitary member named Gerardo Gutierrez Uribe, aka "Jerry".

[11][12] Following the assassination, Antonio Navarro Wolff accepted the nomination of AD/M-19;[13] he later finished third with 12.7% of the vote, losing out to César Gaviria who subsequently appointed him health minister.

She compiled his letters and photographs in the 2015 book De su puño y letra, and later became a member of the Colombian Chamber of Representatives and Senate.